CN107222697A - A kind of video laminating module applied on unmanned plane - Google Patents

Abstract

The invention discloses a video superimposition module applied to an unmanned aerial vehicle. The video superposition module includes a main controller, a power supply circuit, a video superimposition chip, a standard video signal analog output circuit, and a video signal output module. There are sensor expansion interface circuit, miniSD card interface circuit and USB interface circuit, the main controller adopts STM32 microcontroller, and the video overlay chip adopts DP7456 which supports common Chinese. The video overlay module of the present invention is more practical, and compared with the traditional video overlay module in terms of hardware structure and software system design, it has been greatly improved. It can be applied on both man and machine, and has good compatibility.

Description

A video overlay module applied to drones

technical field

The invention relates to the field of video processing, in particular to a video superimposition module applied to drones.

Background technique

Video overlay OSD (On Screen Display) is to overlay date, parameters and other information on the original video. This technology is applied to drones, which can superimpose flight data on the output video of the camera, and then transmit it to the receiving end through the image transmission system (referred to as image transmission), which is usually used for FPV (First Person View). The receiving end intuitively understands the flight status of the aircraft through real-time images and flight data.

At present, the most used video overlay modules at home and abroad are all originated from the minimosd project on Google. The project version ended in 2012, and the final version number is 2.0. Due to the technical limitations of that era, the hardware solution used Atmel's 8-bit microprocessor ATMEGA328 as the main control chip, and the video character overlay chip used Maxim ) company’s MAX7456, the current existing technology still uses the hardware structure and software system of this video overlay module, because of the lack of internal resources, the function only completes the reading of flight data and superimposes it on the image, and does not support Chinese display. After reading these data, the operator needs to go through a series of conversions to know the current flight status of the drone. Another disadvantage of the video overlay module is that it cannot superimpose video information normally when the image transmission signal is lost or the image transmission system fails, so the module needs to power on the camera first or both at the same time.

Contents of the invention

In order to solve the above problems, the present invention provides a video overlay module applied to unmanned aerial vehicles. The video overlay module is more practical, and compared with the traditional video overlay module in terms of hardware structure and software system design, it has been greatly improved. , can be applied to special drones such as aerial survey drones, aerial photography drones, and reconnaissance drones, and has good compatibility.

In order to achieve the above object, the technical scheme that the present invention takes is:

A video superimposition module applied to drones, the video superposition module is between the camera monitoring equipment and the image transmission system, and is used to superimpose the data of the flight controller or sensor expansion module to the camera monitoring equipment after processing In the image, it is wirelessly transmitted to the image receiving system of the ground station through the image transmission system, and is read and processed by the operator; specifically, the video overlay module includes a main controller, a power circuit, a video overlay chip, a standard video signal An analog output circuit and a video signal output module, the main controller is provided with a sensor expansion interface circuit, a miniSD card interface circuit and a USB interface circuit, the main controller adopts an STM32 microcontroller, and the video overlay chip adopts a commonly used DP7456 in Chinese.

Wherein, the mini SD card interface is used to record flight data, which is similar to a "black box" function.

Wherein, the video superimposition module simulates and outputs a PAL video signal through a standard video signal analog output circuit, and when the image is lost or the image transmission system fails, it still normally superimposes and displays the flight data of the UAV in real time.

The present invention has the following beneficial effects:

Using a 32-bit controller with stronger performance and richer resources as the main controller of the video overlay module can quickly receive the data from the flight controller, and through calculation integration, the results are displayed in a graphical way, which is intuitively displayed. The current flight attitude of the man-machine. So that the operator does not need to distract energy to calculate the current flight attitude. For the sake of stability and reliability, a standard video signal analog output circuit is added to the hardware circuit to generate a PAL video signal to prevent video signal loss or image transmission system failure from superimposing information on the video. Part of the Chinese display can be supported by using the chip DP7456 that supports Chinese video overlay display.

Description of drawings

Fig. 1 is a schematic structural diagram of a specific application example in the embodiment of the present invention.

Fig. 2 is a structural block diagram of a video overlay module applied to a drone according to an embodiment of the present invention.

Fig. 3 is the peripheral circuit of the video conditioning chip MAX7452 in the embodiment of the present invention.

Figure 4 is the peripheral circuit of the video overlay chip DP7456 in the embodiment of the present invention.

Fig. 5 is the miniSD card circuit in the embodiment of the present invention.

detailed description

In order to make the objects and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Fig. 1-Fig. 2, the embodiment of the present invention provides a video overlay module applied on the UAV. After processing, the data of the sensor expansion module is superimposed on the image from the camera monitoring equipment, and wirelessly transmitted to the image receiving system of the ground station through the image transmission system, which is read and processed by the operator; specifically, the video superimposition module It includes a main controller, a power supply circuit, a video overlay chip, a standard video signal analog output circuit, and a video signal output module. The main controller is provided with a sensor expansion interface circuit, a miniSD card interface circuit and a USB interface circuit. The device adopts STM32 microcontroller, and the video overlay chip adopts DP7456 which supports common Chinese. The mini SD card interface is used to record flight data, which is similar to a "black box" function. The video overlay module simulates and outputs a PAL video signal through a standard video signal analog output circuit, even when the image is lost or the image transmission system fails, the flight data of the UAV is normally superimposed and displayed on the video signal in real time

The peripheral circuit of the video conditioning chip MAX7452 is shown in Figure 3. The MAX7452 integrates a second-order low-pass filter inside, which can effectively suppress the input noise of the circuit and ensure the image quality. The internal integration of the chip is high, which greatly reduces the cost. The chip inputs the video signal collected by the camera device through the Vedio sig in port, then processes and amplifies the necessary output gain, and finally outputs the video signal to the next stage for processing through the Vedio sig out port. In addition, the chip integrates a video loss monitoring function. When the video signal is lost or the image of the camera equipment is lost, the 8-pin LOSA of the chip will output a high level, and the LED light-emitting diode connected to this pin will light up, indicating that the video is lost. , at this time, a PAL video signal is output from the chip internally.

The peripheral circuit of the video overlay chip DP7456 is shown in Figure 4. The DP7456 video overlay chip integrates an electrically erasable programmable memory, which can ensure that data will not be lost when power is off. In addition, the chip integrates a video driver, synchronization Separator and video separation switch greatly improve the integration of the chip and effectively reduce the cost. The chip uses a 27MHz crystal oscillator to work, and is programmed through the SPI serial interface of the P3 port in Figure 4, with 256 pre-installed Characters and graphics are available for users to edit through SPI online programming. The main working principle of this circuit is to process the video input signal of the BNC port of P2, superimpose the pre-programmed characters and graphics on the video, and output the video to the wireless image transmission system through the BNC port of P1.

The main control peripheral circuit is composed of STM32F405RGT6 chip, including input/output port, clock oscillator circuit, LED indicator circuit, reset circuit, etc. This circuit is mainly responsible for collecting the signal collected by the sensor for processing and controlling the video superimposition circuit.

In order to support the plug and play of USB devices, the video overlay module also designs USB input and output circuits. In order to connect STM32F4 series chips with USB OTG, ST’s STMPS214STR chip is used as the front-end power processing circuit, and then communicates with the main controller through the USB interface. Chip connection, so that it can be directly connected to the computer through the USB interface, eliminating the need for the previous video overlay module to use the USB to TTL circuit to connect through the serial interface, the connection is faster and more stable.

The miniSD card circuit is shown in Figure 5. The main working principle of the MiniSD card circuit is to connect to the main controller through 5 pull-up resistors, and connect the other end to the miniSD card, which supports up to 64GB, and uses SPI to communicate.

The power supply circuit consists of two parts, one is to stabilize the voltage of the lithium battery, and the other is to provide the whole circuit to work after being stepped down by the REG1117-3.3 chip. The power supply circuit is reliable and stable, and can realize linear voltage regulation function.

Example 1

The video overlay module implemented in this paper is applied to the X8 fixed-wing aerial survey aircraft of the unmanned aerial vehicle laboratory of Jilin Institute of Chemical Technology, and with the aerial measurement device and high-power map system, the heading, GPS latitude and longitude, airspeed, The video of parameters such as flight altitude and flight mileage is superimposed and recorded in the miniSD card.

Example 2

The video overlay module implemented in this paper is applied to the six-rotor aerial photography UAV in the unmanned aerial vehicle laboratory of Jilin Institute of Chemical Technology, and with the high-definition image transmission transmitting and receiving system, the flight altitude, flight attitude, battery voltage, GPS star search quality, etc. The information is superimposed on the video, which is convenient for understanding the attitude and status of the aircraft during aerial photography, and improves the reliability of the equipment.

The video overlay module implemented in this paper has redesigned the hardware circuit, using the latest 32-bit microprocessor STM32 of STMicroelectronics, which is more powerful than ATMEGA328 of ATMEL, with faster processing speed and more internal resources. many. .Because the main controller adopts a 32-bit microcontroller, the video overlay module implemented in this implementation runs more smoothly. After processing various information obtained by the flight controller, after calculation, the cumbersome data is converted into graphics and displayed, which is more intuitive. Display the flight status of the drone. .The video overlay module implemented in this implementation comes with a mini SD card interface, which can record flight data and complete the function similar to "black box". .The native USB interface of the video overlay module implemented in this implementation does not need a computer USB to TTL circuit to connect to the flight control, which is convenient for users to upgrade firmware or view data. .The video overlay module implemented in this implementation has the function of PAL video generation. Even if the video signal is lost or the video transmission system fails, there will be flight parameters superimposed on the video, allowing the operator to complete the return flight or other operations according to the flight parameters (such as GPS information) Function. .The video character overlay chip adopts the DP7456 chip that supports commonly used Chinese fonts, and can support part of the Chinese display, which is convenient for the operator to read and understand intuitively. .In order to make the video overlay module more stable and reliable, the power input part has added circuits such as voltage stabilization and filtering, and added a lot of logic judgment functions in the software design, which can set low voltage alarm, height alarm, and geographic fence alarm etc., intuitively superimpose and display data or graphics on the video to remind the operator. .The video overlay module implemented in this implementation supports the access of sensor modules, and can support various sensors without flight control, such as air pressure sensors, temperature and humidity sensors, etc., which is convenient for users to use and expand. To sum up, the video overlay module implemented in this paper is more practical, and compared with the traditional video overlay module in terms of hardware structure and software system design, it has been greatly improved. It can be applied to special drones such as reconnaissance drones, and has good compatibility.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (3)

1. A video overlay module applied on unmanned aerial vehicles, characterized in that the video overlay module is between the camera monitoring equipment and the image transmission system, and is used for superimposing the data of the flight controller or the sensor expansion module after processing into the image transmitted by the camera monitoring equipment, and wirelessly transmitted to the image receiving system of the ground station through the image transmission system, which is read and processed by the operator; specifically, the video superimposition module includes a main controller, a power circuit, a video Overlay chip, standard video signal analog output circuit, video signal output module, the main controller is provided with sensor expansion interface circuit, miniSD card interface circuit and USB interface circuit, the described main controller adopts STM32 microcontroller, the described The video overlay chip adopts DP7456 which supports common Chinese. 2. a kind of video overlay module that is applied on unmanned aerial vehicle as claimed in claim 1, is characterized in that, described miniSD card interface is used for recording flight data. 3. a kind of video overlay module that is applied on unmanned aerial vehicle as claimed in claim 1, it is characterized in that, described video overlay module simulates the video signal of outputting a PAL system by standard video signal analog output circuit, when image loss or When the image transmission system fails, the flight data of the UAV will still be superimposed and displayed in real time.